Struct Partition

pub struct Partition<T: Read + Seek> { /* private fields */ }

A Partition allow you to refer to a part of the file. It consume the input file.

The input offset is the first byte that will be accessible. The user of the Partition won’t be able to seek before it, and it will be considered the offset 0 of the Partition The input lenght is the number of byte that can be read with this Partition. The last readable byte from the input file is input_offset + input_len

Examples

use std::io::{Cursor, Read, Seek, SeekFrom};
use io_partition::Partition;

let some_value = (0..30).collect::<Vec<u8>>();
let input_file = Cursor::new(&some_value); //0, 1, 2, 3 ... 99

let mut partition = Partition::new(input_file, 10, 20).unwrap();

let mut buffer = [0];
partition.read_exact(&mut buffer).unwrap();
assert_eq!(buffer, [10]);
partition.read_exact(&mut buffer).unwrap();
assert_eq!(buffer, [11]);

assert!(partition.seek(SeekFrom::Current(-10)).is_err());
partition.seek(SeekFrom::End(-1)).unwrap();
partition.read_exact(&mut buffer).unwrap();
assert_eq!(buffer, [29]);

partition.seek(SeekFrom::End(-3));
let mut buffer_large = [0; 6];
assert_eq!(partition.read(&mut buffer_large).unwrap(), 3);
assert_eq!(buffer_large, [27, 28, 29, 0, 0, 0]);

Implementations

impl<T: Read + Seek> Partition<T>

pub fn new(file: T, start: u64, lenght: u64) -> Result<Partition<T>>

Create new Partition, with the specified input file, start and lenght

This will check that the file is big enought at creation, and the cursor will be located at the beggining of the file.

Trait Implementations

impl<T: Debug + Read + Seek> Debug for Partition<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T: Read + Seek> Read for Partition<T>

fn read(&mut self, buf: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize, Error>

Like read, except that it reads into a slice of buffers.

fn is_read_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Reader has an efficient read_vectored implementation.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>

Reads all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Reads all bytes until EOF in this source, appending them to buf.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Reads the exact number of bytes required to fill buf.

fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Pull some bytes from this source into the specified buffer.

fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Reads the exact number of bytes required to fill cursor.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self>

where Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

fn chain<R>(self, next: R) -> Chain<Self, R>

where R: Read, Self: Sized,

Creates an adapter which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self>

where Self: Sized,

Creates an adapter which will read at most limit bytes from it.

impl<T: Seek + Read> Seek for Partition<T>

fn seek(&mut self, pos: SeekFrom) -> Result<u64>

Seek to an offset, in bytes, in a stream.

fn rewind(&mut self) -> Result<(), Error>

Rewind to the beginning of a stream.

fn stream_len(&mut self) -> Result<u64, Error>

🔬This is a nightly-only experimental API. (seek_stream_len)

Returns the length of this stream (in bytes).

fn stream_position(&mut self) -> Result<u64, Error>

Returns the current seek position from the start of the stream.

fn seek_relative(&mut self, offset: i64) -> Result<(), Error>

Seeks relative to the current position.

impl<T: Read + Seek> Write for Partition<T>

fn write(&mut self, _: &[u8]) -> Result<usize>

Do not use this write function. It will always fail. It is just here because some library require this to have the Write trait to make this work with this (rust_vfs)

fn flush(&mut self) -> Result<()>

Always suceed. It is useless to call it

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Writer has an efficient write_vectored implementation.

fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored)

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adapter for this instance of Write.